Well, after the Science Center, the only other area to go to in Celestia is the Crustacean Empire. Then, you have to complete two instances: the Chancel and the Trial of the Spheres. I don't think that these would give you enough experience to level up to Legendary. I suggest doing some side quests to help you level. One side quest gave me close to 20000 experience!

You don't give your school, so it is semi-dependant on that, but overall, if the MOBs aren't a problem, you should be fine.

Why do I mention school, well, it is the level 58 spells and the last two dungeons. For my lifer, I would want my lvl 58 spell before the last two dungeons. (Why? I find 'Spheres' needs an 'attack all' spell, but it may just be me.) For other schools, such as death, it isn't as important (The dragon is nice, but a good player can survive all the bosses without).

I have taken 4 characters completely through CL now, and most of the time I was level 56-58 when I was finishing the science center, and level 60 during the last dungeon, and things worked out fine.

yea sry to say but it is. thats the lvl i got to floating land and the lvl most of my other friends did

Ah, you must have come to Celestia directly after fighting Malistaire, at level 48 and did no side quests. Your fine. Don't worry about what other people say, they just came in at grandmaster and therefore are a few levels higher then you at any given time. All it means is once your done with the Trial (or Test) of Spheres you will have to do some extra side quests to get to Legendary.

if you are working on the same place as a higher level and you are a lower level that means you are more skilled than them. example- level 11 getting to krokotopia is better than level 16 getting there.

ok now i am lvl 56 in the crustacean empire for fire. am i still below lvl?

Wouldn't say there is anything such as below level. If you are leveling properly, you should have been at least lvl 8 starting KT, 18 starting MB, 28 starting MS and 38 starting DS. Most people say those levels are below level. You would need a bit of side quests after Malistaire to get to 48 and start CL, but hey, happens to me on all my wizards! It's your choice how you level up, there is no such thing as under leveled. Just if you find an area hard, go back and do some side quests to level up and make life easier for yourself. 54 on Science Center? Except for my death (the only of my wizards that was grand when CL came out, was too lazy to level up rest back then =D) I'm usually that level starting Science Center. Believe it or not, I was level 55 starting Crab Empire on my Balance wizard, and ended up level 57 when I ended CL, doing story quests only in that period! Just, as I said, make sure the area isn't too hard for you at the level you are at. But to me, level 56 on Crab Empire is pretty good! Don't listen to people who say you're under level.

You obviously made it that far at your current level - so you are doing fine. Some people do no side quests and hit CL "early", some do all side quests (like me) and my 3 previous wizards hit legend in Science Center without even touching Grizzle.

So it's up to you where you want to go from here. If you want to have your level 58 spell and be legend for the final Trials quest - then do some side quests.